Head Bolts?

[Crazy_C]

Are the head bolts on the A20A engines reusable? I'm doing a top end rebuild in a few weeks, and I was just wondering if the bolts are reusable or if I need to get new ones? If anyone knows, that'd be a great help! The service manual doesn't say anything about replacing the head bolts, so I guess they're reusable.

Cheers

[POS carb]

i've reused mine a few times...

[A18A]

they are indeed reusable ones. It's TTY (torque to yield) bolts that you shouldn't re-use. They're the ones that you tighten to a certain torque, then tighten another X degrees

[POS carb]

here comes the science:
The yield strength or yield point of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible.
So, as long as the recommended torque spec does not exceed the yield strength, and the mechanic who installed them did not over tighten to the yield, they are reusable. If they were over-torqued it is possible to damage them and make them unusable.

[Crazy_C]

It has never had the head off so the head bolts are Honda fitted them!! Literally all my engine has ever had is oil changes and spark plug and filter changes!! It has averaged less than 4000 miles a year, so it's all as Honda built it and had only ever been serviced by Honda.